Vacuum switch



R. P. LEONARD VACUUM SWITCH Jan. 13, 1959 Filed Jan. 14. 1957 2Sheets-Sheet 1 WMW MM. 5 h 0 Z /1111!!! i\\\\\\ 3 7. i g m litm mm mmw IINVENTOR.

Jan. 13, 1959 R. P. LEONARD VACUUM SWITCH Filed Jan. 14, 1957 2Sheets-Sheet 2 United States Patent VACUUM WITCH Redford P. Leonard,Santa Barbara, Calif., assignor to Penta Laboratories,Inc.,'SantaBarbara, Calif., a corporation of Caiifornia ApplicationJanuary 14, 1957, Serial No. 634,043

'8 Claims. (Cl. 200-87) Thisinvention relates to an electromagneticallyactuated vacuum switch.

A principal object of this invention is to :provide anelectromagnetically actuated vacuum switch having .a reciprocallymounted spring urged armature within an evacuated cylinder andwhereinthearmature is movable toan operative position and is arranged'to move to asecond operative position upon application of a field of ,magnetic fluxabout the armature.

A feature Of this invention is thatrall .moving parts .of the switchassembly are completely contained in the evacuated housing so that thereneed be no translation of motion through the housing Wall.

Another feature and advantage of this invention is that in thefirstcondition of operation certain contact points of the switch areforcefully spring urged into positive .mechanical and electrical unionand in the second condition of operation certain other contact pointsare magnetically urged into positive mechanical and electrical union.

A still further feature and advantage of the invention is th'atthearrangement and structure of movable parts allows the contact points tobe joined so as to be insensitive to ambient mechanical vibrations.

Another object of the invention is to provide the switch arrangement ina housing formed to telescopically receive a solenoid which may beremovably positioned around :the exterior of the housing sectionadjacent the armature .of the switch. Because of this feature thesolenoid may .bereplaced when worn or defective. In addition thereplaceable solenoid feature of the invention allows solenoids ofvarious electrical characteristics to be used in .combinationwith theswitch so as to impart greater flexibility thereto.

Another object of this invention is to provide a vacuum switch of highsensitivity, fast re-action time and grigidityiof structure sutlicientto allowthe switch to be used-under conditions of high voltage and highcurrent.

Other objects of the present invention will become apparent upon readingthe "following specification and referring to the accompanying drawingsin which similar characters of reference represent corresponding partsin each of the several views.

-.-Inthedrawings:

Fig. '1 is an elevational view of the housing of the preferredembodiment of the vacuum switch of the in- .vention.

Fig. :2 is a'scctional view of the embodiment of Fig. '1.

:Fig. 3 is an enlarged fragmentary view of the armature portion of theswitch assembly of Figs. -1 and 2.

Fig. 4;is a sectional perspective of a modification of the invention.

.Referring now to the drawings the preferred embodimentofthe inventionas illustrated in/Figs. l, 2 and 3 comprisesahousing A which is sealedto the atmosphere andevacuated. Armature assembly B is mounted withinhousing A to respectively open and :close contact points l2.and J13.also mounted .within the housing. .Armature I 2,868,922 Patented Jan.13, 1959 '2 assembly B is actuated by magnetic flux from a solenoid Dmounted exteriorly of the housing.

In greater detail the housing comprises a cylindrical section closedatone end by a cap 16 and opening at'the other end .to an.electrical'contact point'chamber 18. The armature assembly comprisesashaft 20 axially aligned in the center of tube '15 with a terminalportion 21 thereof projecting exteriorly ofthehousing through cap .16..The interior portion 22 of shaft 20 terminates adjacent the oppositeend of tube '15. Two cylindrical armature sections .25 and 26areco-axially mounted on shaft 20. Cylindrical section 25 and 26 eachhave an inside diameter substantially smaller than the inside diameteroftube 15. Section 25 isafiixed to'shaft 20in a permanent-position by asetscrew 28. Armature section 26 is reciprocally moun-tedon shaft 2!)and positioned on the end of the shaftadjacent chamber 18.

Armature'sections '25 and 26 are both recessed as at 30 and 31respectively to receive a helical spring 34. Helical spring-34 is thusarranged to urge the reciprocally mounted armature section 26 away fromarmature 25 and into chamber .18. Movement of section 26 into chamber 18is restrained by a shaft 38 mounted within chamber 18 and arranged tocarry a fixed terminal 12 of contact point 12. The bottom end '35 ofarmature section 26 is formed with a bracket v36 flanged outwardly toprovide contact pointsupport ears 37 and 37 Movable terrninallZ ofcontact v:12 is arranged in alignment with terminal 12 on ear 37 Themechanical interactionef the two contacts 12* and 12 provides anelectrical circuit between shaft 3.8. and armature assembly 3, and alsoforms a stop to limit'movement of armature section 26. A shaft 39 isprovided within chamber 18 to mount a fixed terminal l3 above andaligned with terminal 13 of contact point 13 .mounted on ear37 Shafts 38and 39 project outwardly through .the Walls of chamber 1?! to formterminal leads 40 and 41 respectively.

Reciprocally mounted armature section 26 is aligned with the respectiveterminals of contact points 12 and 13. This alignment ismaintained bytwo pins 44 affixed toarmature section 25 and slidably engaged withapertures '46 formed in the adjacent surface of armature section 26.Thus armature section 26 is restrained against relative rotationalmovement by pins 44.

.Solenoid D comprises a coil of wire wound to form an annulus 45 of adiameter slightly largerthan the outside diameter of tube .15.

In operation the solenoid D is-positioned over tube 15 so'thatth-eccoils of the solenoid surround armature sections 25 and 26. As hasbeen hercin'be'fore described spring 34 normally urges contact point 12in the closed position whereat contact point 13 is open as illustratedinFig. 2. -When solenoid D is electrically energized .there is produceda field of magnetic flux within armature sections 25 and 26. Thearmatures are made of. soft iron orother material which is capable ofrapidly being magnetized when influenced by a magnetic field but afterremoval of the field immediately looses the magnetic polarization. Whensolenoid D sets up the magnetic flux through sections 25 and 26, section26 is magnetically forced againstsection 25 because of the magneticattraction exerted between the two sections and by solenoid D.

When armature section 26 is magnetically urged toward section 25 contactpoint 13 is closed and contact point 12 is open thus breaking thecircuit between terminal 40 and terminal 21 and making the circuitbetween terminal 41 and 21. It is obvious that upon de-energizingsolenoid D that armature section .26 will return to its normal conditionWhereat contact point 12 is closed and contact point 13 is open.

It ispreferable that shaft 20, pins 44 and helical spring 34 be formedofnon-magnetic materials. The shaft pins and spring when non-magneticnot only prevents flux loss throughout the armature assembly but alsoprevents binding of the respective parts during energization of solenoidD. Thus with only armature sections and 26 formed of magnetizablematerial the maximum amount of magnetic force is available to pullarmature section 26 towards the stationary section 25.

Helical spring 34 may be formed of various resilient metals. However ifthe switch is to be used in areas of high ambient temperature it hasbeen found that spring 34 formed of tantalum and tungsten isparticularly satisfactory because this alloy has the property ofretaining temper at high temperatures.

Housing A is formed of a material sufficiently nonporous to be capableof maintaining a vacuum within the housing. The walls of tube 15 must beformed of a material which is non-magnetic so as to prevent a shieldingof the flux between the solenoid D and armature assembly B. It has beenfound that glass or ceramic materials are suitable to form housing A.

In Fig. 4 there is provided a modification of the invention. Theembodiment of Fig. 4 has a housing with an armature assembly 51substantially identical to armature assembly B of Figs. 1, 2 and 3except that the end 55 of the reciprocating armature section 56 isprovided with a birfurcated tip 58 joined by a cross member 59. Thecross member mounts a contact point 60 on the top and on the bottom ofthe plate. Matching con tacts 61 and 62 are provided adjacent the twocontacts 60. Contact 62 is mounted on a shaft 65 below plate 59 o andcontact 61 is mounted between the bifurcated tips 58 by a bracket 66.Thus in operation when a solenoid D is placed around housing 50 so as toprovide a field of magnetic flux for armature assembly 51 the embodimentof Fig. 4 will operate in the same manner as hereinbefore described inconnection with Figs. 1, 2 and 3. Thus during energization of thesolenoid contact point 60 is engaged with contact points 61. Uponrelease of the magnetic field contact point 60 is engaged with contactpoint 62 by virtue of the force effected by spring 68 of the armatureassembly.

In the embodiment of Fig. 4 the contact point chamber 69 is formed oftwo axially mounted dielectric cylinders 70 and 71. interposed betweenthe two cylinders is a conductive ring 72 which is attached to bracket59 so as to form a terminal connection 73. The bottom of chamber 69 issealed by a concave conductive plate 75 to provide a recess for theterminal end 78 of shaft 65.

Although the foregoing invention has been described in some detail byway of illustration and example for purr poses of clarity ofunderstanding, it is understood that certain changes and modificationsmay be practiced within the spirt of the invention as limited only bythe scope of the appended claims.

What is claimed:

1. An electromagnetically actuated circuit breaker movable to first andsecond conditions of electrical conductivity within a chamber sealed toatmosphere comprising, within the chamber, a conductive member havingone terminal end projecting exteriorly of said chamber, a conductiveshaft having one terminal end projecting exteriorly of said chamber, atwo element armature means mounted on said shaft with a first elementslidably movable on said shaft to make and break electrical contact withsaid conductive member, said first element electrically connected tosaid shaft, said first element movable to a first position in electricalcontact with said conductive member to render an electrical circuitbetween said shaft and said conductive member and to a second positionout of electrical contact with said conductive member, means to normallyforce said first element of said armature means to one of said twopositions in spaced relation to said second element, the two elements ofsaid armature means formed of magnetizable material whereby when saidarmature means is subjected to magnetic flux the two elements of saidarmature means become magnetized and said first element is magneticallymoved closer toward said second element into the other of said twopositions.

2. An electric switch comprising: a housing forming a chamber sealed tothe atmosphere; a shaft having a portion thereof within the chamber; anarmature assembly mounted on said shaft within said chamber; saidarmature assembly having a fixed section, a movable section reciprocallymovable on said shaft toward and away from the fixed section, and springmeans to urge the movable section away from the fixed section;electrical contacts mounted within said chamber movable to first andsecond conditions of electrical conductivity; electrical leads extendingexteriorly of the housing and connected to the respective saidelectrical contacts; said shaft and movable section comprising one ofsaid leads; fixed means within said chamber to restrain movement of saidmovable section at a predetermined distance from said fixed sectionwhereat said movable section is positioned to cause said contacts to bein the first condition of electrical conductivity, said fixed andmovable sections formed of highly magnetizable metal; andelectromagnetic flux generating means disposed exteriorly of saidchamber and arranged to create magnetic flux about said armatureassembly to magnetize said sections and magnetically cause said movablesection to move toward said fixed section whereat said movable sectionis positioned to cause said contacts to be in the second condition ofelectrical conductivity.

3. An electric switch comprising: a housing having a chamber sealed tothe atmosphere; a shaft having a portion thereof within the chamber; anarmature assembly mounted within said chamber on said shaft; saidarmature assembly having a fixed section rigidly connected to saidshaft, a movable section slidably mounted on said shaft and movabletoward and away from the fixed section, and spring means to urge themovable section away from the fixed section; fixed contact means Withinsaid chamber to restrain movement of said movable section at apredetermined distance from said fixed section whereat the fixed meansis in electrical contact with the movable section; said fixed andmovable sections formed of highly magnetizable metal; electromagneticalflux generating means disposed exteriorly of said chamber and arrangedto create magnetic flux about said armature assembly to magnetize saidsections and magnetically cause said movable section to move toward saidfixed section to open the electrical contact between said fixed contactmeans and said movable armature section; and electrical leads extendingexteriorly of the housing and connected to the fixed contact means andthe movable section respectively said shaft being formed of a highlyconductive material and electrically connected to said first and secondarmatures to provide a high conductivity path between said armatures.

4. An electric switch comprising: a housing forming a chamber sealed tothe atmosphere; an armature assembly mounted within said chamber; saidarmature assembly having a shaft having a first portion mountedexteriorly of said housing and a second portion mounted within saidchamber; a first armature means mounted in a fixed position on thesecond portion of said shaft; a movable armature means reciprocallymounted on said second portion of said shaft and movable toward and awayfrom the fixed armature means; and spring means to urge the movablearmature means away from the fixed armature; fixed electrical contactmeans within said chamber positioned to restrain movement of saidmovable armature means at a predetermined distance from said fixedarmature means whereat the fixed contact means is in electrical contactwith the movable armature means; said fixed and movable armature meansformed of high magnetizable metal; electromagnetic flux generating meansdisposed exteriorly of said chamber and arranged to create 5 magneticflux about said armature assembly to magnetize said armature means tomagnetically cause said movable armature means to move toward said fixedarmature means to open the electrical contact between fixed contactmeans and said movable armature means; and said movable armature meanselectrically connected to said shaft; and an electrical lead extendingexteriorly of the housing connected to said fixed contact means; saidshaft being formed of a highly conductive material and electricallyconnected to said first and second armatures to provide a highconductivity path between said armatures.

5. An electric switch according to claim 3 and wherein said armatureassembly is provided with means to restrain relative rotational movementof said movable armature means with respect to said fixed armaturemeans.

6. An electric switch according to claim 3 and wherein said movablearmature means is provided with an electrical contact and said armatureassembly is provided with means to restrain relative rotational movementof said movable armature means with respect to said fixed armature meansin a position to align said armature contact point with said fixedcontact means.

7. An electric switch according to claim 3 and wherein 6 said shaft andsaid spring means are formed of nonmagnetic material.

8. An electric switch according to claim 3 and wherein said armatureassembly is provided with pin means fixed to one said armature means andslidably engaged with the other armature means to restrain relativerotational movement of said movable armature means with respect to saidfixed armature means with said pin means, said shaft, and said springmeans being formed of non-magnetic material.

References Cited in the file of this patent UNITED STATES PATENTS946,215 Geissinger Jan. 11, 1910 1,175,323 Wikander Mar. 14, 1 9162,001,579 Leece et al. May 14, 1935 2,029,267 Leece et a1 Jan. 28, 19362,131,942 Evans et al Oct. 4, 1938 2,156,974 Doan May 2, 1939 2,170,961Borgkvist Aug. 29, 1939 2,360,941 Eitel et a1 Oct. 24, 1944 2,485,024Vale et al Oct. 18, 1949

